Effects of an energy-restricted low-carbohydrate, high unsaturated fat/low saturated fat diet versus a high carbohydrate, low-fat diet in type 2 diabetes: A 2-year randomized clinical trial.
Effects of an energy-restricted low-carbohydrate, high unsaturated fat/low saturated fat diet versus a high carbohydrate, low-fat diet in type 2 diabetes: A 2-year randomized clinical trial. J Tay, CH Thompson, ND Luscombe-Marsh et al. Diabetes, Obesity & Metabolism 2018;20:858-871.
To examine whether a low-carbohydrate, high-unsaturated/low-saturated fat (LC) diet improves glycemic control and CVD risk factors in overweight and obese patients with T2D, compared to a high-carb (HC) control diet.
"Enrolled: 115 adults with T2D 66 males, 49 females Mean age: 58y Diabetes duration - 6y LC, 8y LF Completed 2 years: 61 (53%) Included in analysis: 115"
"E-matched hypocaloric diets (LC vs HC) combined with aerobic/resistance exercise (1 hour, 3d/week) via class provided for subjects. Weeks 1-12: individual, biweekly instructional meetings; provided with ""key foods"" amounting to ~30%total E. Subjects completed daily food records. Thereafter: meetings were monthly and subjects got foods or vouchers to buy food on alternating months. "
"Low-carb (LC) Targets E - individualized with ~30%E reduction for weight loss Carb - 14%E (<50g/d); after week 24, 20g/d added Protein - 28%E Fat - 58%E (35% MUFA, 13% PUFA); <10%E saturated fat Intake at 22-24 months (ranges and means at every 3 months also available) E: 1707kcal Carb: 83g/d; 19%E Protein: 105g/d; 25%E Total fat: 98g/d; 50%E Saturated fat: 22g/d; 11%E MUFA: 25%E, PUFA: 11%E"
"Target: 14% then increased Intake: 19%"
"Target: 58% Intake: 50%"
"HC diet (lowfat, low-glycemic index diet; avoid refined processed carbs; GI target 46) Targets E - individualized with ~30%E reduction for weight loss Carb - 53%E Protein - 17%E Fat - 30%E (15% MUFA, 9% PUFA); <10%E saturated fat Intake at 22-24 months (ranges and means published for every 3 months) E: 1757kcal Carb: 216g/d; 48%E Protein: 79g/d; 18%E Total fat: 55g/d; 27%E Saturated fat: 18g/d; 9%E MUFA: 11%E, PUFA: 4%E"
E targets set at ~500-1000kcal/d deficits and were matched for diet arms throughout study; both arms adjusted for additional carb grams added in LC arm after week 24.
"Primary: HbA1c Secondary: insulin, C-reactive protein (CRT), glycemic variability (GV, via continuous glucose monitoring), anti-glycemic medication effect score (MES, calculated based on the potency and dosage of diabetes medication), weight, body composition, CVD and renal risk markers, HOMA index 2 assessed β cell function (HOMA2-%B) and insulin resistance (HOMA2-IR), ketones. "
"Estimated marginal mean changes from baseline. Statistical significance reported only for BG differences. Both groups achieved clinically meaningful, equivalent reductions in HBA1c and weight loss. Reduction in blood pressure were similar. The LC maintained greater improvements in lipid profile, diurnal blood glucose stability and reductions in diabetes medication (reduction in meds use double in LC diet group compared to HC diet group). "
"FBG and other measures WG: NR BG: N Fasting glucose LC: +0.3 HC: -0.4 BG NSS 6 other measures of glycemic control (eg min/max glucose, total glucose per min, glucose range) all improved on LC diet and 5/6 improved on LF diet, but all BG differences were NSS."
"WG: NR BG: N LC: -0.6% HC: -0.9% BG NSS"
"WG: NR BG: N LC: +0.2 HC: +0.1 BG NSS"
"WG: NR BG: Y LC: +0.02 HC: -0.1 BG SS p=0.004"
"WG: NR BG: N LC: +0.2 HC: +0.1 BG NSS"
"WG: NR BG: Y LC: -0.1 HC: +0.1 BG SS p=0.001"
"WG: NR BG: N BG NSS LC: -6.8 kg HC: -6.6 kg BG NSS Both groups reduced waist size, fat mass but BG NSS"
"WG: NR BG: N LC: -2.0 HC: -3.2 BG NSS "
"WG: NR BG: N LC: -1.2 HC: -2.0 BG NSS "
"WG: NR BG: N LC: -2.6 HC: -1.8 BG NSS "
"WG: NR BG: N HOMA2-IR LC: -0.3 HC: -0.2 BG NSS HOMA2-%B LC: -5.6 HC: -5.8 BG NSS "
"WG: NR BG: N C-reactive protein LC: -0.6 HC: -0.8 BG NSS "
"WG: N BG: Y Antiglycemic Medication Effect Score (MES) based on medication potency and dosage: LC: -0.5 HC: -0.2 BG SS p=0.03 MES reduction≥20% [n(%)] LC: 22 subjects (38%) HC: 9 (16%) BG SS p=0.04 MES reduction≥50%[n(%)] LC: 12 subjects (21%) HC: 8 (14%) BG NSS "
"Renal function (eGFR, creatinine clearance, albuminuria) WG: NR BG: N eGFR: reductions occurred both groups (-4 in LC group, -3 in HC group); levels remained in normal to mildly depressed range. BG NSS No subject left the study because of adverse events related to treatment. Data on adverse events in supplemental table. "
"At 2 years LC: 33/58 (56.9%) retained HC: 27/57 (47.4%) retained Unable to comply with diet cited as reason for leaving study: 2 in LC group and 6 in HC group."
"""Whilst there may not be a one-size-fits-all dietary approach for obesity and T2D management, these data suggest that diets differ in their efficacy in improving glycemic control and reducing CVD risk. These results provide support for the long-term safety, clinical efficacy and potential therapeutic role of the LC in long-term T2D management."" "
AHA - American Heart Association;
ALT - alanine aminotransferase;
AMDR - acceptable macronutrient distribution range;
AST - aspartate aminotransferase;
BG - between study groups;
BHOB - beta-hydroxybutyrate;
DBP - diastolic blood pressure;
E- energy, caloric intake;
eGFR - estimated glomerular filtration rate;
FBG - fasting blood glucose;
GGT - gamma-glutamyl transferase;
HDL-C - high-density lipoprotein cholesterol;
iGFR - isotope glomerurar filtration rate;
LDL-C - low-density lipoprotein cholesterol;
NAFLD - non-alcoholic fatty liver disease;
NR - not reported (or data needed for calculation not available);
N - no;
NA - not applicable;
NS - not specified;
NSS - not statistically significant;
SBP - systolic blood pressure;
SS - statistically significant;
TG - triglyceride;
total C - total cholesterol;
V - varied, mixed;
WG - within a study group;
WMD - weighted mean difference;
Y - yes
Number of People in Studies:
3,296 Enrolled in randomized controlled trials on 25% or less carbohydrates
2,626 Completed randomized controlled trials on 25% or less carbohydrates
79.67% 82% completion of studies
Duration of Trial
1 -2 years
# of Trials
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